<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <script>
    // 数组修改，直接取出数组下标后赋值
    let arr = [];
    arr[0] = 100;
    console.log(arr);

    let arr1 = ['a', 'b', 'c']
    arr1[0] = 'z'
    console.log(arr1);

    let arr2 = ['张三', '李四', '王五']

    for (let i = 0; i < arr2.length; i++) {
      arr2[i] = arr2[i] + '你好'
    }
    console.log(arr2);

  </script>
</body>

</html>